1. Field
The present invention relates to the field of data communications. In particular, this invention relates to a system and method to eliminate degradation of information being transferred.
2. General Background
In digital communication networks, calls can be made through one or more tandem connections. A xe2x80x9ctandem connectionxe2x80x9d comprises a networking device (e.g., a Private Branch Exchange xe2x80x9cPBXxe2x80x9d) coupled between tandem digital channels. In order to optimize bandwidth (the amount of information transmitted per second), compression is performed. Normally, whenever lossy compression information is compressed, a certain amount of that information is lost.
Normally, for audio communications, upon encountering a tandem connection, compressed audio over the first tandem channel undergoes (i) decompression, (ii) transmission to a second tandem channel, and (iii) compression. These decompression and compression operations cause significant degradation in the clarity of the audio as well as increased signal latency during transmission. To solve this problem, techniques have been developed to detect the presence of a tandem channel and to pass the compressed audio directly through a networking device, thereby eliminating additional decompression and compression operations. The disadvantage associated with the current technique is that there is no method to verify that the tandem channels are operating at the same rate and with the same compression algorithm. This is important in switched networks where the audio and/or data compression algorithms are negotiated. If a compressed audio signal is transferred to a tandem channel running a different compression algorithm and/or at a different rate, severe degradation of the audio signal will result.
Hence, it would be advantageous to provide a system and method for detecting the presence of a tandem channel and, at the same time, detecting the compression algorithm and rate of the tandem channel. This would provide more flexibility for switched networks to eliminate decompression and compression operations, and thus, would assist in reducing distortion of information.
One embodiment of the present invention relates to a method for reducing the distortion of data passed through a tandem connection. This is accomplished by transferring the data in a compressed format instead of decompressing and recompressing that data. The method comprises an initial operation of exchanging information concerning characteristics of signal lines, separated by the tandem connection, through the tandem connection. If these signal lines possess the same characteristics, such as supporting the same transmission rate and utilizing the same compression function, information is transferred through the tandem connection in its compressed format.